1. Field of the invention
The present invention concerns an end leaf, as well as a binding element containing such an end leaf.
In particular, the invention concerns an end leaf of the type which is meant to be used in combination with binding means with which a bundle of loose leaves can be bound.
2. Description of the related art
It is known that when binding a bundle of loose leaves on the front side and/or back side of this bundle, a relatively rigid end leaf made of cardboard or synthetic material can be provided. When such a conventional end leaf is used in combination with binding means which keep the bound bundle of leaves fixed near the bound-in edge, there is a disadvantage in that it is difficult to open such an end leaf due to its rigidity. Such binding means may for example consist of binding elements with a rigid, U-shaped back section, whereby the bundles of loose leaves can be attached in this back section by means of heat-sensitive glue; of binding elements containing two sections or such, in between which the bundle, together with the end leaves, is fixed at one edge; and in the simplest embodiment also of staples which are provided through the bundle at one edge.
In the case of cardboard end leaves, the above-mentioned problem was already solved by locally breaking the fibers of the cardboard, so that a folding line is created.
However, for end leaves which are mainly formed of synthetic material, in particular of a relatively rigid type of plastic, there is no good solution at hand yet. Providing a cold folding line in synthetic material, as is the case with cardboard, is little efficient and will rather rapidly cause a crack. Providing a hot folding line often implies an improvement thanks to the local bonding of the material, but the technique is very unstable, as the dilution has to be carried out with much precision, which entails a level of difficulty which is too high to be able to do this with the required precision in a mass production process. Moreover, the problem still remains that the synthetic material will easily crack after said dilution.
The invention aims an end leaf which is mainly formed of synthetic material, offering an efficient solution to the above-mentioned problem.
To this end, the invention concerns an end leaf of the above-mentioned type, characterized in that the end leaf at least consists of a leaf made of synthetic material and a connection strip or strip-shaped part firmly attached to the edge of said leaf which is suppler than the above-mentioned leaf. Thus, the end leaf with the strip-shaped part can be situated along the edge to be bound of the bundle of documents to be bound, so that, after the binding operation has been carried out, the end leaf can be easily opened thanks to the presence of the suppler strip-shaped part.
The strip-shaped part may consist of any material whatsoever, but preferably it is also made of synthetic material.
Another interesting possibility is that it is made of paper.
According to a preferred embodiment, the end leaf is provided with means which stiffen the strip-shaped part, whereby these means are situated at a distance from the above-mentioned edge of the leaf, such that, between the leaf and the above-mentioned means, there will remain a non-stiffened, supple part. These means preferably consist of a strip of material which is attached onto the strip-shaped part, for example made of paper, cardboard or such.
The use of these means, in particular of such a reinforcing strip of material, offers the advantage that a relatively stable edge is obtained, although a supple and flexible part remains present in the end leaf. Such a stable edge is particularly advantageous when such an end leaf is used in combination with a binding element having a U-shaped back section. Indeed, such a reinforced edge can be more easily pushed in the U-shaped form of said back section, together with a bundle of loose leaves, than in the case where no reinforcement is provided.
The invention also concerns binding elements provided with such an end leaf, in particular binding elements whereby such an end leaf is a fixed part thereof.